Fluid pressure operated apparatus



2 Sheets-Sheet 1 Q N n5 m w w s N. a 3 m m nlzi HUME) KN M w T k T 1 BN m 0 O n v M NE W a 1 W April 11, 1939. K. E. EVRELL FLUID PRESSURE OPERATED APPARATUS Filed Sept. 22, 1937 April 11, 1939. i EVRELL I 2,154,038

FLUID PRESSURE OPERATED APPARATUS Filed Sept. 22, 1937 2 Sheets-Sheet 2 JKaZQb 11772 22 EvreZZ Patented Apr. 11, 11939 UNITED [STATES PATENT OFFICE Aktiebolaget Bolinder-Munktell,

Eskilstuna,

, Sweden, a corporation of Sweden Application September 22, 1937, Serial In Sweden October 3, 1936 3 Claims.

The present invention relates to apparatus operated by a fluid under pressure, such as compressed air or liquid, delivered from a common source of supply and adapted to actuate a plurality of servo-motors arranged to transmit power to diflerent places of consumption. In particular, the invention relates to a controlling device for such apparatus.

The primary object of the invention is the provision of means to ensure that one or more of the servo-motors always can be supplied with suflicient working fluid at the desired pres-' .0 reference may be had to the accompanying drawings forming a part of this specification and the following description thereof. Two embodiments of the invention are illustrated in the drawings, the first embodiment showing the invention as applied to an actuating device for log carriages and the second embodiment showing the invention as applied to a controlling apparatus for pressure diecasting machines.

In the drawings:

Figure L-shows a rear' elevation of a log carriage provided with a fluid pressure operated device in accordance with the invention;

Figure 2 is a side elevation of the log carriage shown in Figure 1;

Figure 3 is a top view of the log carriage;

Figure 4 shows in a more diagrammatic manner a section of the controlling device employed in the log carriage:

Figure 5 is a detail of Figure 4 on a larger scale;

Figure 6 is a section taken on the line VI-VI of Figure 4 on a larger scale.

Referring to Figs. l3, the reference numerals I and 2 designate two haulage chains by means of which the log carriage is moved and which are travelling in opposite directions, as indi cated by the arrows I' and 2' respectively. The chains I and 2 are in permanent mesh with chain wheels 3 and 4, respectively, mounted in the carriage. Reference numerals 5 and 8 designate brake pedals by which the chain wheels I and 4 respectively can be locked. The braking mechanism forms no part of this invention and is not shown in detail in the drawings. If the chain wheel 3 is locked the log carriage follows the chain I meshing with the said wheel in the direction of the arrow I towards the saw frame. If the chain wheel 4 is locked and the chain wheel 3 released the carriage will move in the opposite direction. For the purpose of holding a log on the carriage there are provided dogs or jaws I and l pivotally secured to a jaw head 9. By means of a hand wheel iii the gripping device 1-9 may be turned, independently of the pressure actuated mechanism to be described hereinbelow, about an axis parallel to the direction of move ment of the carriage, and by means of a lever II the gripping device may be turned about ashaft I2 so that it will bepossible to lower the jaws down to the log carrier I3, in order that they shall not hinder a log from being rolled upon the carriage,

The log carriage is fitted with servo-operated devices for clamping or gripping the log and for side shifting and turning the same about its own axis. In the embodiment illustrated, the power necessary for supplying the servo-motors with fluid under pressure is derived from the haulage chains I and 2 by means of a transmission device in the form of a differential gear the primary or driving wheels of which are the chain wheels 3 and 4. The transmission device is pref-, erably in the form described in my co-pending patent application Serial No. 123,709, filed February 2, 1937, or of any other suitable type. By means of the transmission gear which is enclosed by a casing II, a pump I9 is driven so as to produce ahydraulic pressure.

As will be best seen from Fig. 4, the pump is is supplied with liquid from a liquid container through a conduit 2i. The container 20 is closed by a small cover 22 provided with an opening 23. By means of a conduit 24 and a flexible pipe 25 the discharge side of the pump I9 is connected to a control valve 26 formed as a four-way valve and manually operable by means of a handle 21. The flexible pipe 28 connects the valve 26 with the container 20.

The jaws l and 8 are linked to a cross-piece 29 connected to a rod 30 which at its other end forms a piston lI adapted to slide in a cylinder 32 slidably mounted on the shaft i2. The spaces above and below the piston 3i are connected with the valve 24 by means of the conduits 33 and 34. A by-pass conduit 3! provided with a pressure .relief=- valve II connects the conduit 24 directly to the container 20. The pressure relief valve 35 is heldfin closed position by a helical spring 31, the tension of which is such that the valve will be openedit the pressure in the conduit 24 rises above the highest. permissible value.

, Mountedin the container is a control valve 38 having an inlet passage 39 and an outlet passage 45, (see. P 8, 5). By means of a helical spring 4|,itbe one end of which rests againsta ring 42 screwed. into the casing of the valve 38 and provided with an aperture 43, a piston 44 is forced into the inlet passage 39 and thereby prevents flow or liquid from the passage 39 to end carriesa-pinion as (see Fig. 6).

the passage 49'. The inlet passage 39 is connected to the pipe by means of, a conduit 45. A flexible pipe connects "the outlet passage 43 to a four-way valve 41 operable by a handle 48 and to' another control valve 49 which is designed inthe same manner as the control valve 38. By means of conduits 58 and 5| the fourway valve connected to a stationary cylinder 52. A piston 53 adapted to slide in the cylinder 52 is connected to "the cylinder 32 by a piston rod 54. Upon movement of the piston 53 the cylinder 33 1 together with the jaw head 9 and the jaws T, 8wlll be shifted sideways in the one or the other direction.

The outlet passage 55 of the control valve 49 is connected by. means of a conduit 55 to a fourway valve 57 which can be manually operated by a handle 58. By means of two conduits 59 and the four-way valve.5'| is connected to a cylinder 5| rigidlyiconngctedto the cylinder 32 and provided with" a stationary piston 62 and a" rotary piston 53 mounted on a shaft 84 which at its outer t By the pistons 62 andgl gthecylinder 5| is divided into two compartments 86 and 51 which may be brought intocommunication with the four-way valve 51 by me'a'nsofthe conduits 59 and 58. The jaw head 9 is'rotatably mounted on an axial elongation 'of'the cylinder 32 and formed into a gear wheel 59 adapted to mesh with the pinion 55. It will thu$be-seen that upon rotation of the shaft 54 the jaw head together with the jaws and the log 78 clamped between them will be turned around the axis of the piston rod 30. By means'of conduits H and 12 the four-way valves 41 and 51 are connected to each other,

and by means of a flexible return pipe 13 the said valves are connected to the liquid container 20. The space behind the piston of the control valve 49 is connected to the pipe 13 by means of a conduit I4.

The apparatus described operates in the following manner.

If a log is to be clamped between the jaws l and 8 the four-way valve 25 is brought into the position shown in Fig. 4. Liquid under pressure is then-supplied from the container 28. through the conduit 2|, the pump IS, the conduits 24 and 25, the valve 25 and the conduit 33 to the upper space of the cylinder 32. The piston 3| will then be moved downwardaas viewed in Fig. 4, so that the jaws will be brought into engagement with the log 10. Liquid which is contained in the cylinder 32 below the piston 3| will thereby be returned to the container 20 through the conduit,

the cylinder 52 on the right-hand side of the piston 53.

During the time in which the jaws l and 8 are moving towards the log III the resistance acting against the movement of the piston 3| is comparatively' small and, as a result thereof, the pressure of the liquid in the conduits 24, 25 and 33 will be considerably lower than the pressure at which the piston 44 of the control valve 38 can be moved inwardly so as to connect the conduits 45 and 45. Preferably, the spring 4| counteracting such movement of the piston 44 has an initial tension oi! the order of 80% of the maximum pressure at which the non-return valve 35 opens the conduit 35. During the movement of the jaws I, 8 towards the log, the pressure in the conduit 25 is considerably lower than 80% of the maximumpressure, with the result that the control valve 38 will prevent liquid from flowing into the pipe 45. As soon, however, as the jaws are firmly pressed against the log, the pressure of the liquid rises above 80% .of the maximum pressure and the piston 44 of the control valve will be moved inwardly against the resistance of the spring 4| sov that liquid can flow from the conduit 45 to the conduit 45 and through the valve 41 into the conduit 5| and the right-hand side of the cylinder 52. be moved towards the left. Liquid contained in the left-hand side of the cylinder 52 is returned to the container 28 through the pipes 50, I2 and I3. a

The movement of the gripping device in lateral direction requires as a rule only a comparatively small power. Were itnot for the control valve 38 a reduction in the pressure of the liquid caused by arapid movement of thepiston 53 would be transmitted through the conduit 25 to the upper space of the cylinder 32 so that the pressure at which the jaws are forced towards the log might be decreased to such an extent that the log would no longer be held with the necessary power. The

control valve 38, however, prevents a reduction opposite direction, the body of thefour-way valve 41 is turned by means of the handle 48 through an angle of 90. The pressure conduit 45 will then ,communicate through the valve with the conduit 50, while the conduit 5| will be connected to the return pipes 12 and I3. In the intermediate position of the handle 48, the cylinder 52 is entirely shut off from the conduit 45. I

In order to actuate the turning device, and

handle 58 of the four-way valve 51 is turned through an angle of 45 from the position shown in the one or the other direction, as the case may be. Pressure liquid will,thowever, not how through the conduit to the valve 51 unless the following two conditions are'fulfllled. Firstly, the pressure in the conduit 25 must be so high that the control valve 38 opens the connection between the conduits 45 and 45; this condition prevails if the jaws I and 8 have been brought into engagement with the log 10. Secondly, the pressure in the conduit 45 must be so high that the The gripping device will then ausaoaa I piston of the control valve 4! opens the connection between the conduits I and 58; this second condition is fulfilled if the valve 41 is in its intermediate position in which the conduit 46 is entirely shut off from the cylinder 52, or if the piston 53 has reached either of its end positions, or if the resistance exerted against the movement of the piston 53 is strong enough to produce a counter-pressure which can move the piston of the control valve inwardly against the resistance of the spring of the said valve. If the valve 51 is so adjusted that it connects the conduits 56 and 59 to each other, the space '6 oi the cylinder 6| will be filled with liquid under pressure and the piston 03 will be turned in a clockwise direction. This turning movement is transmitted to the jaw head 8 by means of the shaft 64 and the gear wheels 6! and 89. In this position oi the four-way valve 51, the space 61 of the cylinder 6i will'be brought, through the pipe 60, into communication with the return pipes H and 13. If the valve 51 is adjusted such that the pressure conduit 56 is brought into communication with the conduit 60, the space 61 will be filled with liquid under pressure and the, 1aw head will be turned in the opposite direction.

To release the jaws from the log, the body of the four-way valve 26 is turned through a right angle so that the liquid under pressure will fiow from the conduit to the conduit 34 and move the piston 3| upwardly whereby the jaws will be turned out of engagement with the log. In the intermediate position of the valve 26 the gripping device is put out 01 operation.

By means of the conduit H, liquid which leaks along the piston 01 the control valve 9 can flow to the return pipe 13.

Many changes and variations in the specific construction of apparatus for carrying the invention into effect will occur to those skilled in the art and it is to be understood that the scope of the invention is not limited to the embodiments hereinbeiore illustrated and described by way of example, but is to be considered as including all forms of apparatus falling within the scope of the appended claims when they are construed as broadly as is consistent with the state of the prior art.

What I claim is:

1. In a log carriage for saw mills, a gripping device for holding a log during the sawing operation, a first servo-motor for actuating said gripping device, means ior side shifting said gripping device, a second servo-motor for actuating said shifting means, an impeller for delivering fiuid under pressure, a first conduit for connecting said impeller with said first servo-motor, a second conduit for connecting said impeller with said second servo-motor, and a control valve in said second conduit, said control valve being adapted to be opened upon increase in the pressure of said fluid above the pressure required for actuating said first servo-motor.

2. In a log carriage i'or saw mills, a gripping device for holding a log during the sawing operation, a first servo-motor for actuating said gripping device, means for turning said gripping device, a second servo-motor for actuating said turning means, an impeller for delivering fiuid under pressure, a first conduit for connecting said impeller with said first servo-motor, a second conduit for connecting said impeller with said second servo-motor, and a control valve in said second conduit, said control valve being adapted to be opened upon increase in the pressure of said fluid above the pressure required for actuating said first servo-motor.

3. In a log carriage for saw mills, a gripping device for holding a log during the sawing operation, a first servo-motor for actuating said gripping device, means for side shifting said gripping device, a second servo-motor for actuating said shifting means, means for turning said gripping device, a third servo-motor for actuating said turning device, an impeller for delivering fluid under pressure, a first conduit for connecting said impeller with said first servo-motor, a second conduit for connecting said impeller with said second servo-motor, a third conduit for connecting said impeller with said third servo-motor, a first control valve in said second conduit, said control valve being adapted to be opened upon increase in the pressure of said fluid above the pressure required for actuating said first servomotor, and a second control valve in said third conduit, said second control valve being adapted to be opened upon increase in the pressure required for actuating said second servo-motor.

KALEB EMILEVRELL. 

